—CO2 cartridges come in two basic
varieties: threaded and non-threaded.
Some inflators are specifically designed to
work with one type, while others can work
with both.

—Cartridge size varies. The small
cartridges you can buy in bulk at a sport-ing-goods store are typically 12-gram
unthreaded and often don’t provide
enough gas to fill a mountain bike tire.
Sixteen-gram cartridges will work for most
small-volume XC tires, and 25- or 30-gram
cartridges can handle larger air volumes
and 29er tires.

—All CO2 inflators get extremely cold
when the gas is released to the point
where you can freeze the valve or even
your skin. Many inflators have features that
are designed to keep your hands insulated.

—CO2 gas is not compatible with most
sealants because it comes out of the car-

Fast riders prefer CO2 inflators when it comes to fixing a flat tire trailside. They’re the quickest way to put air
in a tire short of packing a compressor
and a really long extension cord on your
next ride. They’re not the cheapest method, as each cartridge typically sells for
a few bucks and only houses enough to
inflate one tire, but if you’ve ever experienced arm fatigue when using an underpowered mini pump to inflate a tire, you’ll
appreciate the luxury and speed a good
CO2 system provides. Unfortunately, early
inflators were plagued by cheap plastic
construction that inevitably caused a
frustrating hissing of all the gas escaping
with an early release. The good news is
that the inflators in this test are head and
shoulders above the old-school ones. In
our test, not a single CO2 cartridge went
to waste. After months of testing, we put
together a list of CO2 inflators we’d be
happy to have on the trail with us when
faced with a flat tire.

tridge so cold. This can freeze the sealant,
rendering it unable to fix a puncture. If
you’re fixing a flat trailside with CO2, it’s
best to install a tube.

—Cartridges are single-use, as once
the cartridge is punctured, the pressure will
slowly leak from most any regulator. Since
these are single-use, we highly recommend
recycling the steel cartridges to reduce
waste.

—All inflators in this test are compatible
with both Schrader and Presta valves.

—CO2 regulators vary in complexity—
from super-stripped down and simple to
fancy and loaded with features. We are
testing some of each in this shootout. Most
companies make several models, which
means the rider can choose how many features are included.